Evaluation of Two Post-Processing Analysis Methods of Proton Magnetic Resonance Spectroscopy in Glioma Tumors

BACKGROUND

Magnetic resonance spectroscopy (MRS) is a non-invasive diagnostic and the neuroimaging method of choice for the noninvasive monitoring of brain metabolism in patients with glioma tumors. ¹H-MRS is a reliable and non-invasive tool used to study glioma. However, the metabolite spectra obtained by ¹H-MRS requires a specific quantification procedure for post-processing. According to our knowledge, no comparisons have yet been made between spectrum analysis software for quantification of gliomas metabolites.

OBJECTIVE

Current study aims to evaluate the difference between this two common software in quantifying cerebral metabolites.

MATERIAL AND METHODS

In this analytical study, we evaluate two post-processing software packages, java-based graphical for MR user interface packages (jMRUI) and totally automatic robust quantitation in NMR (TARQUIN) software. ¹H-MRS spectrum from the brain of patients with gliomas tumors was collected for post-processing. AMARES algorithms were conducted to metabolite qualification on jMRUI software, and TARQUIN software were implemented with automated quantification algorithms. The study included a total of 30 subjects. For quantification, subjects were divided into a normal group (n=15) and group of gliomas (n=15).

RESULTS

When calculated by TARQUIN, the mean metabolites ratio was typically lower than by jMRUI. While, the mean ratio of metabolites varied when quantified by jMRUI vs. TARQUIN, both methods apparent clinical associations.

CONCLUSION

TARQUIN and jMRUI are feasible choices for the post-processing of cerebral MRS data obtained from glioma tumors.

1H-MRS application in the evaluation of response to photo-thermal therapy using iron oxide-gold core-shell nanoparticles, an in vivo study

BACKGROUND

Photo-thermal therapy (PTT) has been at the center of attention as a new method for cancer treatment in recent years. It is important to predict the response to treatment in the PTT procedure. Using magnetic resonance spectroscopy (MRS) can be considered a novel technique in evaluating changes in metabolites resulted from PTT.

METHODS

In the present project, we conducted an in vivo study to assess the efficacy of ¹H-MRS as a noninvasive technique to evaluate the response to treatment in the early hours following PTT. The BALB/c mice subcutaneously bearing tumor cells (CT26 cell line) were scanned by ¹H-MRS before and after PTT. Iron oxide-gold core-shell (Fe₃O₄@Au) as PTT agent was injected into intra-peritoneal at first and then irradiated by NIR laser. Single-voxel Point RESolved Spectroscopy (PRESS) sequence (TE = 144) was used, and metabolites alternations were evaluated by the non-parametric Wilcoxon test. Besides, Nanoparticle (NP) relaxometry was conducted for negative contrast agents' potentials.

RESULTS

MRS choline (Cho) peak dramatically reduced 24 h post-PTT (p = 0.01) and lipid peak as a marker for necrosis of tumor elevated (p = 0.01) just in group 3 (NPs injection + laser irradiation) 24 h after the procedure.

CONCLUSION

¹H-MRS showed its potential as a method in detecting the changes in metabolites and revealing the outcome accurately. Response to photo-thermal therapy evaluation was achievable only one day after PTT and proved by a 10-day follow-up of the tumor size. Iron oxide-gold core-shell can also be used as a negative contrast agent in MRI images during therapy.

Monitoring of the choline/lipid ratio by 1H-MRS can be helpful for prediction and early detection of tumor response to nano-photo-thermal therapy

Nanotechnology-based photothermal therapy (NPTT) is a new emerging modality of cancer therapy. To have the right prediction and early detection of response to NPTT, it is necessary to get rapid feedback from a tumor treated by NPTT procedure and stay informed of what happens in the tumor site. We performed this study to find if proton magnetic resonance spectroscopy (1H-MRS) can be well responsive to such an imperative requirement. We considered various treatment groups including gold nanoparticles (AuNPs), laser, and the combination of AuNPs and laser (NPTT group). Therapeutic effects on CT26 colon tumor-bearing BALB/c mice were studied by looking at alterations that happened in 1H-MRS signals and tumor size after conducting treatment procedures. In MRS studies, the alterations of choline and lipid concentrations and their ratio were investigated. Having normalized the metabolite peak to water peak, we found a significant decrease in choline concentration post-NPTT (from (1.25 ± 0.05) × 10^-3 to (0.43 ± 0.04) × 10^-3), while the level of lipid concentration in the tumor was slightly increased (from (2.91 ± 0.23) × 10^-3 to (3.52 ± 0.31) × 10^-3). As a result, the choline/lipid ratio was significantly decreased post-NPTT (from 0.41 ± 0.11 to 0.11 ± 0.02). Such alterations appeared just 1 day after NPTT. Tumor shrinkage in all groups was studied and significant changes were significantly detectable on day 7 post-NPTT procedure. In conclusion, the study of choline/lipid ratio using 1H-MRS may help us estimate what happens in a tumor treated by the NPTT method. Such an in vivo assessment is interestingly feasible as soon as just 1 day post-NPTT. This would undoubtedly help the oncologists make a more precise decision about treatment planning strategies. Monitoring of the choline/lipid ratio by ¹H-MRS can be helpful for prediction and early detection of response to nano-photo-thermal therapy.

Neurochemical metabolite alterations of the occipital lobe in migraine without aura by proton magnetic resonance spectroscopy

BACKGROUND

Migraine without aura is the most common type of migraine headache, accounting for about 80% of all migraines. The aim of the present investigation was to determine the neurochemical metabolite alterations in the occipital lobe of patients suffering from migraine without aura using proton magnetic resonance spectroscopy (1H-MRS).

METHODS

Fifteen patients suffering from migraine without aura with an occipital plaque and 16 healthy controls were included in this study. Changes in the neurochemical metabolites in the occipital lobe were assessed using 1H-MRS. The ratios of N-acetylaspartate (NAA) to creatine (Cr), choline (Cho) to Cr and myo-inositol (MI) to NAA were measured by voxel volume at 8 cm3.

RESULTS

The mean NAA/Cr ratio decreased significantly in patients compared to controls. Cho/Cr and MI/NAA ratios increased significantly in patients. In addition, the duration of the disease and the frequency of headache attacks were significantly associated with a decrease in the NAA/Cr ratio and an increase in the Cho/Cr ratio.

CONCLUSIONS

Migraine without aura shows a significant association with changes in neurochemical metabolites detectable by 1H-MRS in the occipital lobe of patients. In addition, changes in metabolic ratios showed a significant relationship with the duration of the disease and the frequency of headache attacks.